1. Field of the Invention
The present invention relates generally to an electrical control circuit for use with a reverse osmosis unit. More particularly, the present invention relates to an electronic control circuit which sequentially controls the fill, settle and draw operations or cycles of a plurality of settling tanks used with a reverse osmosis unit.
2. Description of the Prior Art
The purification of water by reverse osmosis is a well established technology that is being increasingly used due to problems with the purity of water caused pollution, contaminants and other harmful products within the water. The increasing usage of reverse osmosis technology has resulted in the development and refinement of relatively efficient reverse osmosis systems producing tens of hundreds of thousands of purified water per day that are economically and technically feasible for use in domestic and similar applications.
For relatively large scale reverse osmosis systems, such as systems used by the military settling to purify water, settling tanks are generally provided for the removal of solid contaminants and environmentally harmful agents which will settle to the bottom of the tanks. The water from the settling tanks is then supplied to the reverse osmosis system for purification by the reverse osmosis system.
An electrical control circuit is required to open and close the valves and pumps associated with filling the settling tanks, drawing water from the settling tanks and allowing the contaminants in the water to settle at the bottom of the settling tanks. One possibility is to use programmable controllers as the control circuitry for the settling tank fill and drain operations. Programmable controllers are commercially available from several manufactures such as Allen-Bradley, a Division of Rockwell International Corporation.
While programmable controllers are generally acceptable as a means to control the fill, draw and settle operations of settling tanks, programmable controls are expensive and require the user to have extensive programming skills to program and trouble shoot these devices.
Accordingly, there is a need for an inexpensive and relatively simple in design control circuit which may be used to control the fill, draw and settle operations or cycles of settling tanks which are integral to a reverse osmosis system.